You were 18 years old and writing your first ever final exam of university. You had three sharpened yellow pencils, one blue ballpoint pen, your student ID, a metal reusable bottle of water, and an apple to keep your energy levels up. You were so nervous that your sweaty palms smeared the ink as you answered the questions on the test paper. You couldn’t wait to hand in your test paper, walk out the exam room and forget about that 3-hour ordeal. In anticipation, you glimpse at the loudly ticking clock every 20 minutes and every time you do, time seems to be moving more slowly than before. Even now, years after walking out of that exam room alive, you remember every detail of your experience.

But you don’t remember the information you spent learning all semester that appeared on that final exam.

Both memories described above are consciously remembered, declarative memories, and these types of memories are naturally prone to forgetting. However, why is it that we remember the information about our experience differently from, or better than, information we may have actively tried to remember? It is because our declarative memory is divided into two types: episodic and semantic memory. Episodic memories are made up of information stored from specific personal experiences, while semantic memories are made up of knowledge and facts we have learned. Together, they allow us to combine newly learned knowledge with experiential knowledge to new situations.

Regardless of type, memory naturally degrades over time. Usually, we forget semantic memories much more quickly than we do episodic memories, but we forget nonetheless. While forgetting cannot not be entirely avoided, it can be slowed by improving on memory encoding techniques. While repetition can indeed “refresh” our memory, those memories, especially when learning semantic information, are stronger when processed more elaborately. This levels-of-processing effect essentially means information that is learned multidimensionally creates stronger memories that take longer to fade.

This explains why we may remember something like writing our first-ever final exam (an episodic memory) better than the information we were required to study for that exam (a semantic memory). This is because our episodic memories are often processed with an emotional dimension, such as anxiety or excitement, which helps the deepen the level of processing. Not to mention, emotion is one of the strongest triggers for memory.

Now, this doesn’t mean you have to try to squeeze out tears of joy or sadness to avoid forgetting something. Instead, making yourself work a little harder to learn or remember something can get the job done. For example, engaging multiple senses with images and audio, mapping conceptual connections between facts, telling a story about an idea, and practicing problem-solving rather than reviewing flashcards can more strongly reinforce memory. Whether learning independently or creating learning materials for an audience, allowing for opportunities of deep, multidimensional processing can improve long-term memory in the long run.